PROJECT SUMMARY Assessment of loss of visual function outside the foveal area is an essential component of the management of numerous conditions, including glaucoma, retinal and neurological disorders. Despite the significant progress achieved with the development of standard automated perimetry (SAP) many decades ago, assessment of visual field loss with SAP still has significant drawbacks. SAP testing is limited by subjectivity of patient responses and high test-retest variability, frequently requiring many tests for effective detection of change over time. Moreover, as these tests are generally conducted in clinic-based settings, limited patient availability and health care resources often result in an insufficient number of tests acquired over time, with delayed diagnosis and detection of disease progression. The requirement for highly trained technicians, cost, complexity, and lack of portability of SAP also preclude its use for screening of visual field loss in underserved populations. To address shortcomings of current methods to assess visual function, we have developed the nGoggle, a wearable device that uses a head-mounted display (HMD) integrated with wireless electroencephalography (EEG), capable of objectively assessing visual field deficits using multifocal steady-state visual-evoked potentials (mfSSVEP). As part of the funded NEI SBIR Phase I, we developed the nGoggle prototype using a modified smartphone-based HMD display and non-disposable electrodes. In our Phase I studies, we conducted benchmarking tests on signal quality of EEG acquisition, developed methods for EEG data extraction and analysis, and conducted a pilot study demonstrating the ability of the device to detect visual field loss in glaucoma, a progressive neuropathy that results in characteristic damage to the optic nerve and resulting visual field defects. We also identified limitations of current existing displays and electrodes, as well as potential avenues for enhancing test reliability and improving user interface. Based on the encouraging results from Phase I and a clear delineation of the steps needed to bring the device into its final commercial product form, we now propose a series of Phase II studies. We hypothesize that optimization of nGoggle's accuracy and repeatability in detecting visual function loss can be achieved through the development of a customized head-mounted display with front-view eye/pupil tracking cameras and disposable no-prep electrodes, as well as enhancement of the visual stimulation protocol and data analytics. The specific aims of this proposal are: 1) To develop a customized head-mounted display and enhanced no-prep electrodes for improving nGoggle's ability to acquire users' mfSSVEP with high signal-to- noise ratios (SNR) in response to visual stimulation; 2) To optimize and validate mfSSVEP stimuli design and data analytics to enhance the accuracy and repeatability of assessing visual function loss with the nGoggle. 3) Complete pivotal clinical studies to support FDA approval.